/Engine/Plugins/Online/OnlineServices/Source/OnlineServicesInterface/Public/Online/Sessions.h
This event will trigger as a result of accepting a session invite or joining a session via the platform UI.
[TOnlineEvent](API\Plugins\OnlineServicesInterface\Online\TOnlineEvent)< void(const [FUISessionJoinRequested](API\Plugins\OnlineServicesInterface\Online\FUISessionJoinRequested) &)> OnUISessionJoinRequested()